Background: Curcumin and quercetinare two natural substances with low side effects and has antioxidant activity, anti-diabetic and strong anti-cancer and other health benefits. The aim of this study was the evaluation of these two compounds as anti-cancer agents and their toxicity on murine 4T1 breast cancer cells by MTT method.

Materials and Methods: In this experimental study, after cells culturing in 96-well plate 5, 10, 20, 30, 40 micromolar concentrations of curcumin and quercetin were added to the cells and after incubation during 24 and 48 hours, cell viability were evaluated by MTT method. one way-Anova was used to analysis data. p<0.05 was considered as significant level.

Results: The result of this study showed that IC50 at 24 hours for curcumin was 14.8±4 micromolar and for quercetin 21.7±0.7 micromolar per ml and for 48 hours for curcumin was 21±0.3 micromolar and for quercetin 18.2±0.45 micromolar.

Conclusion: In this study we showed that cell survival were depended on curcumin and quercetin concentration and time of incubation. By increasing the concentration of solution, toxicity have increased and cell survival have decrease at 48 hours more than 24 hours.